Diesel vs gas......................

[blt2ski]

OK folks, there have been a few to many diesel vs gas threads that have shall we say gone to "Hell and a hand basket"! So if all of you would put in you BEST, no flaming reasons for going gas vs diesel, pro and con, I will either leave your thread, or copy and paste pertinant info to the 4 posts of pro and con of diesel or gas. This can include the GM 8.1 vs Dmax or Ford V-8/10 vs PSD etc too.

Be real and honest in you answers, not hear say, flaming etc PLEASE!

If posts are good ones, I will leave, if inflamatory or trolling in nature, they will be deleted! I will get this stick'd to the top for future parusing for those that need this type of info.

Added 6-23-04

We are getting closer to answers I am looking for etc.

Stuff like Ken's - T-Bone posts are good. There are a few others of you that have not posted, some with a 9 point question and answer type to figure out how you went with one or the other. If you are one of those, PLEASE repost in this thread. I may have to look up whom has done this and PM you, but if you think this is you, you now know what to do.

Also, for those of you with $ per gallon for either fuel right now, I would prefer to see a post with ...."in my area, diesel is typically .10 less than unleaded" then explain your numbers. As currently in the Seattle area, diesel and unleaded are any where from 2.05 -2.30 per gallon, with mid test .10 more and premium about .20 more, with equal high low splits. Two weeks ago those prices were upwards of .30 -.40 per gallon more. people were posting $ per gallon that were for me. "I wish" If someone is reading your post a year from now, they may want to know where your paying 1.65, when the price of fuel is over $3 per gallon. Let's keep prices out of it if possible.

Bert and tin tipi, got into a good discusion on the pros and cons of RPM's, drive train etc. I would prefer to NOT see the quote of the other in responding threads, maybe just write a quick wording of re tranny gearing, instead of the whole 40 words or so in that paragragh, so the repsonse is shorter if possible quicker and easier to read etc.

I have deleted some 15+/- posts, that were off topic etc. Please note, I am trying to keep this at the top, as the ONLY gas/diesel thread in this area. So if one is trying to decide, we do not have to go thru this BS any more. As such, I will be deleting ANY future posts close to resembling this type of topic. I may have to change "this" title to a better one, if one has a better sounding title, to be more positive, better claification, let me know here, or in a PM/e-mail, what ever you feel most comfortible with.

Again thank you for all of you that are keeping responses positive, etc.

Also we could use a few more positive reasons to go gas, as many can see I have both gas and diesel, both have a place! Both have positive reasons to buy that fuel, lets keep the threads etc to that purpose only!

Marty

[sharker6]

That's strange, half the information on this thread is wrong or has zilch to do with fuel. The whole gambit has been covered from golf carts to tractors. The fact is, with all other things being equal, diesel will out pull gas, for now.

[BertP]

The whole idea behind this thread, John, is to debate and discuss diesels vs gassers and issues related to them. That's not childish nor a waste of time. Many people come to forums like this one to find help in making a decision on what they should buy. For them, what they have doesn't pull what they need because they may not have a tow vehicle at all. Threads like this one help separate truth from fiction.

Bert

[Sport45]

I think we did give it a break. It had been more than 24 hrs since the last post.

[joheath]

You guys need to give it a break and grow up. What difference does it make if what you have pulls what you need. Get over it!!!!!!

[BertP]

It takes power to burn tires like that. Eventually, the amount of power output by the engine drops to the point that there is insufficient to burn the tires and they hook up. But, that has nothing to do with acceleration except that by using up the available power to burn the tires you lack the excess power and traction needed to accelerate. There is still some available, though, so unless you are impeding the forward movement of the vehicle, acceleration will occur.

Bert

[DavidPhillips]

If your tires are spinning from traction loss, lets say from hard acceleration around 30 mph.

As the output of the engine decreases they stop spinnnig.

Doesn't that indicate a drop in the output to the tires.

[BertP]

DavidPhillips wrote:
Acceleration is defined as the rate at which the velocity changes.

Now if your at 3000 rpm what would the velocity be changing to? You can't go any faster because the speed is directly linked to the rpm. If it can't increase your not accelerating.

So 3000 rpm and 0 rpm are the same when we look at acceleration. The amount of acceleration is 0.

You are removing the time factor. Consider a golf cart: they start their acceleration with the engine switched off. By pressing on the accelerator, the starter is engaged causing the cart and engine to accelerate and, when the engine is turning fast enough, it starts and takes over from the starter. However, for this discussion, it is important to consider what happens at the moment the driver places his/her foot on the accelerator. Both the engine and starter are turning at 0 rpm and the speed is (hopefully) 0 as well. Yet, the cart starts to accelerate. You have to remember that acceleration has a time component. When my truck reaches 3000 rpm, it can be accelerating at the maximum rate that it can. It must shift at that point, but there is no other rpm where my truck can accelerate harder than 3000 rpm.

DavidPhillips wrote:
That's in any gear. If you have another gear you can accelerate after the upshift. At that point you will be in the lower rpm range of that gear and the acceleration will be greater than the acceleration is at 3000 rpm (which is 0 acceleration).

No, it will be at a lower rate of acceleration. At the moment that my truck hit 3000 rpm, it was accelerating as hard as it could. True, if I held it at 3000 rpm, all acceleration would cease, but at the point in time that I hit 3000 rpm, it was accelerating harder than at any other rpm point.

DavidPhillips wrote:
So any acceleration is more than 0. Therefore more, greater, however you say it.

Also think about how you take off spinning your tires if you push to hard on the accelerator. This happens from low rpm.

Ever see someone start spinning wheels as they approach the high end of a gear? No.

No, you don't. That is because the difference in acceleration from 0 to the max acceleration at low rpm is far greater than the difference between the rate of acceleration at low rpm to the rate at high acceleration.

Bert

[DavidPhillips]

Acceleration is defined as the rate at which the velocity changes over time.

Now if your at 3000 rpm what would the velocity be changing to? You can't go any faster because the speed is directly linked to the rpm. If it can't increase your not accelerating.

So 3000 rpm and 0 rpm are the same when we look at acceleration. The amount of acceleration is 0.


That's in any gear. If you have another gear you can accelerate after the upshift. At that point you will be in the lower rpm range of that gear and the acceleration will be greater than the acceleration is at 3000 rpm (which is 0 acceleration).

So any acceleration is more than 0. Therefore more, greater, however you say it.



Also think about how you take off spinning your tires if you push to hard on the accelerator. This happens from low rpm.

Ever see someone start spinning wheels as they approach the high end of a gear? No.

[BertP]

DavidPhillips wrote:
If you get a chance Bert can you explain the gasser redline thing.


I thought the horsepower was supposed to say how fast you can go.

It does, but it is not the only part of the equation. As you mentioned earlier, I can't go any faster in my truck than redline in top gear. So, even if that speed only required 200 HP and my engine can produce 310 HP, it can't go any faster than redline in OD. As mentioned earlier, HP also dictates how hard your rig can accelerate.

DavidPhillips wrote:
So if you go past the max horsepower rpm toward redline some other lower gear kicks in or something.

No, it just keeps accelerating. Remember, just because an engine (diesel or gas) is reving at its max HP rpm doesn't mean that it is developing it max HP. My DMax can produce 310 HP @ 3000 rpm. I have had it to 3000 rpm a number of times over the last 16 months but it has produced 310 HP a total of 0 times. Max acceleration occurs at your max HP point. That doesn't mean that acceleration can't occur at any other point. We know that it can and does all the time. It just isn't max acceleration.

DavidPhillips wrote:
I though the hp was torgue x rpm / 5252

It is. But just because there is an increase in either torque or rpm, there isn't necessarily an increase in HP. If rpm increases but torque decreases, you can have a drop in HP - which is exactly what happens in a gasser. From the max torque point to the max HP point, the torque output is dropping (incidentally, that is also true in most - not all - diesels). Since the torque drop isn't sufficient to nulify the increase in rpm, the HP continues to increase until the max HP point is reached. From that point until the redline, the drop in torque cannot be compensated for by the increase in rpm and the HP drops. Does that help?

DavidPhillips wrote:
Are you talking about the actual red line painted on the tach?

Yes.

Bert

[DavidPhillips]

Acceleration is defined as the rate at which the velocity changes ver time.

Now if your at 3000 rpm what would the velocity be changing to? You can't go any faster because the speed is directly linked to the rpm. If it can't increase your not accelerating.

So 3000 rpm and 0 rpm are the same when we look at acceleration. The amount of acceleration is 0.


That's in any gear. If you have another gear you can accelerate after the upshift. At that point you will be in the lower rpm range of that gear and the acceleration will be greater than the acceleration is at 3000 rpm (which is 0 acceleration).

So any acceleration is more than 0. Therefore more, greater, however you say it.



Also think about how you take off spinning your tires if you push to hard on the accelerator. This happens from low rpm.

Ever see someone start spinning wheels as they approach the high end of a gear? No.

[BertP]

DavidPhillips wrote:
Lower gears are a different story Bert.

When you are in a lower gear you are going to accelerate from the low rpm for that gear to the shift point. It still holds that unless you go to a higher gear you cannot accelerate past redline.

That is true. What I have been talking about, though, is at what rpm point do you realize max acelleration. If you are at the redline in top gear, you aren't acellerating so it is a moot point.

DavidPhillips wrote:
However in the lower gear you will not get to 3000 rpm before shifting. That's plain crazy. If you do you will be holding it in lower gear.

In general, that is true. Most of my shifts happen at around 2000 rpm because I try to soft pedal my truck. But, when it is under load, 3000 rpm can quite easily be reached. I remember climbing out of a valley in BC and my truck was running at 3000 rpm in 3rd gear all the way up. It couldn't grab 4th because that would lower the rpm to a point where insufficient power could be generated to maintain speed. So, it had to stay in 3rd.

DavidPhillips wrote:
You may be right about most gassers higher redline. Don't know. What good would it be?

It gives the advantage that the shift point can be set - under really hard acelleration - to straddle the max HP point. That will give you the max acelleration that vehicle can provide - especially if the tranny has enough gears that a shift causes a minimum drop in rpm.

Bert

[DavidPhillips]

If you get a chance Bert can you explain the gasser redline thing.


I thought the horsepower was supposed to say how fast you can go.

So if you go past the max horsepower rpm toward redline some other lower gear kicks in or something.

I though the hp was torgue x rpm / 5252

Are you talking about the actual red line painted on the tach?

[DavidPhillips]

Lower gears are a different story Bert.

When you are in a lower gear you are going to accelerate from the low rpm for that gear to the shift point. It still holds that unless you go to a higher gear you cannot accelerate past redline.

However in the lower gear you will not get to 3000 rpm before shifting. That's plain crazy. If you do you will be holding it in lower gear.


You may be right about most gassers higher redline. Don't know. What good would it be?

[BertP]

DavidPhillips wrote:
If the engine is already wide open at rev limit you can not accelerate at all.

The max rate of acelleration in my truck is at 3000 rpm because that is where max HP is generated. Since that is also the max rpm of my engine, the tranny will be forced to shift up at that point.

DavidPhillips wrote:
You will accelerate more from 1600 rpm. That is where your highest output is.

No, you won't and no, it isn't. Max output is at (in my DMax) 3000 rpm.

DavidPhillips wrote:
Simply by law of calculating max hp it is going to be at redline on any engine. Therefore no acceleration at all.

No it isn't. Most gassers are redlined quite a bit higher than their max HP point. Only diesels are redlined at their max power point.

Bert

[DavidPhillips]

see above

Bert think about what you are saying.

You just got through proclaiming that the max hp is at 3000 rpm.

If the engine is already wide open at rev limit you can not accelerate at all.

You will accelerate more from 1600 rpm. That is where your highest output is.

Simply by law of calculating max hp it is going to be at redline on any engine. Therefore no acceleration at all.



Please explain this